Ultraviolet (UV) radiation is a form of electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays, ranging from approximately 100 to 400 nanometers (nm). Although invisible to the human eye, UV radiation has significant effects on living organisms and materials.
UV radiation is classified into three types:
- UVA (315400 nm): Has the longest wavelength, penetrates deeply into the skin, and contributes to skin aging and wrinkles.
- UVB (280315 nm): Causes sunburn and plays a major role in skin cancer. It also stimulates vitamin D production in the skin.
- UVC (100280 nm): Has the shortest wavelength and is highly germicidal. It is almost completely absorbed by the Earth's ozone layer and atmosphere, so it does not normally reach the surface.
Applications of UV radiation include:
- Sterilization and disinfection of water, air, and medical equipment.
- Forensic analysis and counterfeit currency detection.
- Curing inks, coatings, and adhesives.
- Medical treatments such as phototherapy for certain skin conditions.
Effects of excessive UV exposure:
- Sunburn
- Premature skin aging
- Eye damage (e.g., cataracts)
- Increased risk of skin cancer
In summary, ultraviolet radiation is an invisible, high-energy form of light with both beneficial uses (such as sterilization and vitamin D synthesis) and harmful effects when exposure is excessive.